rough idle... again...

[pong]

here we go again...

my car is idling rough again...

here is the problem this time...


when i turn on the car.... the idle swings from 1500 - 1800...
when i turn on the aircon... idle stabilizes at 1200...
when i engage the gear... its at 800...

d problem is when the car reaches operating temperature...
regardless of whether the aircon is on or off... idle swings from 1200 - 1500

when gear is engaged... no rough idle...

help pls...

thanks!

[Ferret]

when i turn on the car.... the idle swings from 1500 - 1800...


Massive Idle swing is almost always due to a huge bypass of the MAF/Air flow unit.

Have you checked for a massive vaccuum leak yet?

[rcbrown23]

Could you evaluate a bit Ferret?

Think of me as the ultimate NEWB.;)

My 94 540 seems to be doing the same thing, but not to the extent that "pong's" is. How do I... Check for a hole in the hoses? which one's?

[Ferret]

Could you evaluate

Elaborate? :p



a bit Ferret?

Think of me as the ultimate NEWB.;)

My 94 540 seems to be doing the same thing, but not to the extent that "pong's" is. How do I... Check for a hole in the hoses? which one's?

Okay, I'll stop being a prick now.

If it's doing it on a 540i you're going to want to set the car on fire shortly I think... you'll be looking at manifold gaskets or pcv gaskets, both of which are a bitch to do...

Stick your head under the bonnet and see if you can hear the car making a hissing noise while it's doing it, that's usually the first sign.

[rcbrown23]

Ouch. And... Ouch.

Tomato, Potato... I'm hungover:(

[pong]

crap... all the hoses... and i couldnt find it...
is there an easy way? tried spraying water on the hoses... so that if engine acts weird... then i have found d air intake leak...

[ThoreauHD]

I agree with Ferret. Manifold gasket/vacuum leak. Secondarily, the idle control valve.

[pong]

ok... im about to dunk this car into the lake...

it recently got a top overhaul... vacuum leak...
which in particulr....

did the water thing to all the lines going to the throttle body... none reacted...

idle control valve... placed a working one in there... no change...

maf too....

seals in oil cover, dipstick are ok...

what else should i look at?

[Bin_jammin]

I know it's a different engine, but on my 535 it wouldn't idle at all when the coolant temp switch went bad.